Calhoun County, IL Shrink-Swell Risk

Shrink-swell potential in Calhoun County, IL

Moderate

Soil across 66.6% of Calhoun County, IL comes back "Moderate" in USDA's shrink-swell data, averaging 3.12% linear extensibility. That's a middle reading: not the sharp swings that crack a foundation outright, but enough that grading and drainage are worth getting right.

What this number does and doesn't tell you

This is a countywide, area-weighted figure across every soil survey map unit in Calhoun County, IL - never a reading for one specific parcel. A local geotechnical report, typically $1,000-$5,000 (around $2,700 typical), is the only way to know what one lot in Calhoun County will actually do.

Calhoun County: the real numbers

Calhoun County's soil reading points toward standard foundation practice as the likely outcome, not the exception. A geotechnical report runs $1,000-$5,000, typically around $2,700. Foundation repair, if a specific lot turns out to differ from the county average, runs $5,000-$15,000.

Where this sits nationally

Among the 3,085 rated counties on this site, Calhoun County, IL ranks 1,109 most-constrained nationally, and 85 of 101 within Illinois. Calhoun County, IL is 254 square miles with a population of 4,224.

See how another county compares

Orleans Parish, LA carries this site's most-constrained reading. Napa County, CA and Lee County, SC are worth a look for comparison.

How this reading is built, and its real limits · Moisture management: the cheap fix that works on any soil

Elsewhere in Illinois

Every county in Illinois is on this site, including Douglas County, IL and Fayette County, IL. The full underlying dataset is downloadable directly, one row per county.